The long term objective of this project is to examine the proposition that the physical state of the lipid deposits of early aortic lesions in humans is involved in the progressive development of atherosclerotic lesions. The approach is and has been to exploit physical methods to study both the properties of the isolated molecular species and the behavior of droplets in samples of affected aorta. During the current year, we intend to extend our studies of the pure cholesteryl esters with the objective of understanding the molecular organization of the smectic phase. We hope to develop a procedure for the production of perdeuterated cholesteryl, a molecule which will be of great use in studies of cholesteryl ester phases and of lecithin or other phospholipid interactions with cholesteryl. We also intend to continue our studies of the compositional distribution in human fatty streak tissue, and to attempt to relate our observations to epidemiological factors. BIBLIOGRAPHIC REFERENCES: "Molecular Organization of the Cholesterol Ester Droplets in the Fatty Streaks of Human Aorta" by D.M. Engelman and G.M. Hillman; Journal of Clinical Investigations, Vol. 58, page 997-1007, 1976. "Compositional Mapping of Cholesterol Droplets in the Fatty Streaks of Human Aorta" by G.M. Hillman and D.M. Engelman; Journal of Clinical Investigations, Vol. 58, page 1008-1013, 1976.